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From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] device-dax: fix cdev leak
Date: Thu, 23 Feb 2017 13:20:30 -0700	[thread overview]
Message-ID: <20170223202030.GB26301@obsidianresearch.com> (raw)
In-Reply-To: <148787772308.30127.18437190636864555810.stgit-p8uTFz9XbKj2zm6wflaqv1nYeNYlB/vhral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

On Thu, Feb 23, 2017 at 11:22:03AM -0800, Dan Williams wrote:
> If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
> with a stale device number.
> 
> Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> Cc: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
> Reported-by: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
> Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
>  drivers/dax/dax.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
> index ed758b74ddf0..0f8008dd0b0c 100644
> +++ b/drivers/dax/dax.c
> @@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
>  	dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
>  	rc = device_add(dev);
>  	if (rc) {
> +		cdev_del(&dax_dev->cdev);

This probably should call into unregister_dax_dev and just skip the
device_unregister part.

Once cdev_add returns it is possible for a mmap to have been created,
so cleanup after that point has to go through all the other
unregister_dax_dev steps.

Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@ml01.01.org, Logan Gunthorpe <logang@deltatee.com>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] device-dax: fix cdev leak
Date: Thu, 23 Feb 2017 13:20:30 -0700	[thread overview]
Message-ID: <20170223202030.GB26301@obsidianresearch.com> (raw)
In-Reply-To: <148787772308.30127.18437190636864555810.stgit@dwillia2-desk3.amr.corp.intel.com>

On Thu, Feb 23, 2017 at 11:22:03AM -0800, Dan Williams wrote:
> If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
> with a stale device number.
> 
> Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
> Cc: <stable@vger.kernel.org>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>  drivers/dax/dax.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
> index ed758b74ddf0..0f8008dd0b0c 100644
> +++ b/drivers/dax/dax.c
> @@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
>  	dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id);
>  	rc = device_add(dev);
>  	if (rc) {
> +		cdev_del(&dax_dev->cdev);

This probably should call into unregister_dax_dev and just skip the
device_unregister part.

Once cdev_add returns it is possible for a mmap to have been created,
so cleanup after that point has to go through all the other
unregister_dax_dev steps.

Jason

  parent reply	other threads:[~2017-02-23 20:20 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-23 19:22 [PATCH] device-dax: fix cdev leak Dan Williams
2017-02-23 19:22 ` Dan Williams
2017-02-23 19:22 ` Dan Williams
     [not found] ` <148787772308.30127.18437190636864555810.stgit-p8uTFz9XbKj2zm6wflaqv1nYeNYlB/vhral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-02-23 20:20   ` Jason Gunthorpe [this message]
2017-02-23 20:20     ` Jason Gunthorpe
     [not found]     ` <20170223202030.GB26301-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-02-23 20:27       ` Dan Williams
2017-02-23 20:27         ` Dan Williams

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